I have no idea where they got the infection. They have been in the tank for over 6 months, I have not added any stock in the last 2-3 months

Did you add any plants? Sometimes they can carry them. I got Columnaris 2x from not dipping them before adding to my tanks and now that I've started that I haven't had it since.
It could have also been something in the tap water, that's even more rare but occasionally possible.

Did you add any plants? Sometimes they can carry them. I got Columnaris 2x from not dipping them before adding to my tanks and now that I've started that I haven't had it since.
It could have also been something in the tap water, that's even more rare but occasionally possible.

Did you add any plants? Sometimes they can carry them. I got Columnaris 2x from not dipping them before adding to my tanks and now that I've started that I haven't had it since.
It could have also been something in the tap water, that's even more rare but occasionally possible.

Nothing new, actually added some bamboo shrimp a few moths ago I only trimmed the plants I have. The only thing was one of my GBRs died 2-3weeks ago no sign of infection, injury or anything. My water perimeters have been perfect

I went to Lowes and got extra tubing for my water changer, connectors for the tubing, various pvc pieces for making hiding spots for the fish, and silicone and a caulk gun for resealing my leaky 20 long. Plus a nice little silicone bead smoother so I don't have to get it all on my fingers. In a little while I think I will start tearing out the old silicone!